The frame that holds the lights is made of wood from a small futon I disassembled. The shop lights are 4' wide, and the futon was a little wider than that. I installed casters on the bottom of the frame so had to factor their height into the total height of the frame (I have about 1/2" of clearance between the top of the frame and the bottom of the ping pong table).
The shop lights will be hung by chains (when I find them); they are intended to be raised as the plants grow. The pots are lined up in each bucket to maximize space and reduce water spilling onto the floor. To prevent the floor from getting wet I have put a tarp and drop cloth under the buckets.
To water the plants:
1) Lift the side of the ping pong table where you have to access; it is hinged to allow easy folding. (I would recommend leaving the table up until you need to use it again.)
2) Slide the frame holding the lights so that the seedlings are accessible. The extra width of the frame ensures that you won't need to roll the frame over the tarp or drop cloth. Make sure that your cords are long enough and out of the way when rolling the frame out.
3) Water your plants.
4) Adjust the height of the lights if necessary.
5) Roll the frame back over the plants.